Milking machine pulsator



Patented Aug. 13, 1940 MILKING MACHINE PULSATOR John L. Hulbert, Poughkeepsie, N. Y., assigner to The De Laval Separator Company, New York, N. Y., a corporation ci New Jersey Application May 17, 1939, Serial No. 274,167

6 Claims.

My invention relates to that class of automatic vpneumatically operated devices, commonly called pulsators, for producing and controlling the pneumatic waves of pulsations in the teat cups of milking machines.

The object of the invention is to provide a pulsator which is of simple construction and less expensive to manufacture than those heretofore known but still having equal reliability. The object is attained by utilizing the main feature of the pulsation of my Patent No. 2,138,921, issued December 6, 1938, while modifying and simplifying its construction.

In the pulsator embodying the present invention the construction is such that the space between the valve seats of one pair connects directly through a freely open passage with a small chamber adjacent one end ofthe valve carrier, while the space between the valve seats of the other pair connects, through a restricted passage with a large air chamber freely communicating with a small chamber adjacent the other end of the valve carrier; the valve carrier being positioned to reciprocate in a vertical direction. By this construction and arrangement it is insured that, when not in operation, the valve carrier will always be at one end of its stroke ready for a start, thereby eliminating the special starter valve and ports of the pulsator of my said patent and l eliminate one of the two constricted passages of the said patented pulsator and the required cleaning device therefor.

In the accompanying drawing of my improved pulsator, Fig. 1 is a vertical sectional view showing the conditions with the valve carrier at the lower end of its movement, and Fig. 2 is a similar view showing the conditions with the valve carrier at the upper end of its movement.

l is a pulsator body having a vertical bore 2 in which a loose fitting valve carrier 3 reciprocates and around which are two upper poppet valve seats A and 5 and two lower poppet valve seats 6 and l. Around the valve carrier are two poppet valves, an upper one 8 adapted to contact with the seats 4 and 5 and a lower one 9 adapted to contact with the seats 6 and l. Between and at both sides of the Valves the carrier is reduced in size to permit easy ow of air around and along it. Around the upper end of the bore 2 there is a small chamber III across which extends an impervious flexible partition II and at the lower end of the bore there is a similar chamber I2 and a similar partition I3.

An atmospheric inlet I4 communicates with the central part of the bore 2 and a vacuum passage I5 communicates with the bore beyond the valve seat 4 and the seat l.

The space between the valve seats il and 5 is in free communication with a nipple I6 adapted to receive a rubber tube for connection with the pulsation chambers of a pair of teat cups Il and is in communication, through a restricted orifice i8, oi the type shown in my earlier Patent No. 2,096,807, issued October 26, 1937, with an air chamber I9, of comparatively large volume, in the upper part of the body, which, through chamber IU, communicates with the more distant side of the flexible partition II.

The space between the valve seats 6 and 1-is in free communication with both the nipple 2li, adapted to receive a rubber tube for connection with the pulsation chambers of two teat cups 2l, and through a channel 22, with the more distant side of the lower flexible partition i3.

With the valve carrier 3 and valves El and 9 in the position shown in Fig. l, and the passage I5 connected with vacuum, air, at atmospheric pressure, can ow quickly from the inlet i4 past the valve seat then through nipple 2B to teat cups ZI and through channel 22 to the far side of thepartition I3, which will be therebypushed against the lower end of the carrier 3 and will tend to lmove it upward. This upward `movenfient will be resisted by atmospheric pressure on the upper side of valve 9 and by the partition II which at first is held do-wn by pressure from the charnber I9. At the same time air is exhausted quickly from the teat cups I'I through the nipple l and slowly from the chamber IS through the orice I8 past the valve seat 4 and into the vacuum passage I5.

As the pressure in chamber i9, and through the partition II, against the upper end of the valve carrier 3, slowly reduces, it eventually becomes so weak that the partition i3, under the i influence of full atmospheric pressure, is able to move the carrier upward. As soon as the valve 9 leaves the seat 'I air at atmospheric pressure rushes around its edge and yincreases the pressure below it so that the carrier moves quickly to the upper end of its stroke, as shown in Fig. 2.

Air is now quickly exhausted past valve seat 'I to passage I 5 from the nipple 2l?, cups 2l and, through channel 22, from the under side of partition I3 which then has equal pressure on both kits sides because its upper side is, through leakage around the lower end of the loose fitting carrier, in constant communication with passage I5. Air from inlet I4 quickly lls nipple I6 and teat cups I'I and flows slowly through orifice I8 into 55 chamber I9 and presses the partition l! against the upper end of the carrier. As the pressure builds up it inally becomes strong enough to overcome the resistance due to atmospheric pressure against the under side of valve 8 and forces the carrier down to the position shown in Fig. l. and the cycle is repeated. In this movement air rushing around the edge of valve 8 when it rst leaves seat li increases the downward force so that the movement is completed almost instantecusly.

In a manner similar to that shown in my aforementioned Patent No. 2,138,921 the valve carrier is guided by the walls of the bore but t so loosely that there is no danger of its being stuck by dust, and friction is negligible. The air tight valve action is all by poppet valves which are so proportioned that when the valves once break away from their seats the resistance to movement is so greatly reduced that the valves and carrier complete their stroke almost instantaneously.

The sizes of the exposed ends of the carrier may be so proportioned that they compensate llor its weight and cause the pauses at the two ends of its movement to be of equal time length.

What I claim and desire to protect by Letters Patent is:

l. In a milking machine pulsator, the combination of a body member having two pairs of spaced apart valve seats, a valve carrying member reciprocable in the body member, poppet valves carried by the carrier member, one for each pair of valve seats, sources of high and low pressure, air chambers at opposite ends of said carrier and air passages communicating with the respective chambers adapted, at either end position of the carrier, to be connected, by said valves, one with the source of high pressure and the other with the source of low pressure, to thereby effect the shift of the carrier toward its other end position, one of, said passages being relatively restricted and the other relatively free, so that the shift in one direction is eiTected by a rapid iiow of air into one chamber and a slow exhaust from the other while the shift in the other direction is effected by a rapid exhaust from the first named chamber and a slow ow of air into the second chamber.

2. In a milking machine pulsator, the combination with a body having a bore with poppetvalve seats, a member reciprocable within said bore, poppet valves carried by said member and adapted to cooperate with said seats, air chambers at opposite ends of, the bore, flexible nonpermeable walls closing the bore from the respective air chambers and adapted to press against the opposite ends of said member, sources of high and low pressures, and passages adapted when the member is at either end of the bore to connect the near chamber with the source of high pressure and the far chamber with the source of low pressure, one of4 said passages being relatively restricted so that the air iiow into and out of the same is comparatively slow, the other passage being relatively unrestricted so that the air flow into and out of the same is relatively rapid.

3. In a milking machine pulsator, in combination, a body having a bore with poppet-valve seats therearound, an air chamber at each end of said bore, passages communicating with the respective chambers, iiexible non-permeable walls closing the bore from the respective air chambers, a member reciprocable in said bore, poppet valves carried by ysaid member and adapted to cooperate with said valve seats and, in the reciprocation of said member, to connect, through the passage communicating therewith, the chamber toward which said member has moved with a source of high pressure and, through the passage communicating therewith, the chamber from which said member has moved with a source of low pressure, the two passages being relatively restricted and unrestricted.

4. In a milking machine pulsator, the combination with a body having a vertically extending bore with poppet valve seats, a member reciprocable within said bore, poppet valves carried by said member and adapted to cooperate with said seats, chambers at opposite ends of the bore, exible non-permeable Walls closing the bore from the respective air chambers and adapted to press against opposite ends of said member, sources of high and low pressure, and passages adapted when the member is at either end of the bore to connect the near chamber with the source of high pressure and the far chamber with the source of low pressure, the passage connecting with the upper air chamber being relatively restricted and the passage connecting with the lower air chamber being relatively unrestricted, the upper chamber being of comparatively large volume and the lower chamber being of comparatively small volume.

5. In a millnng machine pulsator in combination a body having a vertical bore with two pairs of poppet valve seats one above and one below the center of length of the bore, a flexible impermeable partition at each end of the bore, an air chamber in communication with the more distant side of the upper iiexible wall and communicating therewith a restricted passage lead ing to the space between the upper pair of Valve seats, a relatively unrestricted passage leading from the space between the lower pair of valve seats to the more distant side of the lower flexible partition, a source of higher pressure in constant communication with the bore between the pairs of. Valve seats, a source of lower pressure in communcation with the two portions of the bore beyond the valve seats, and a valve carrier reciprocable in the bore and having two poppet valves adapted when in the lower position to close communication from the source of lower pressure and open communication from the higher pressure to the space between the lower pair of valve seats, whereby the higher pressure is quickly communicated to the more distant side of the lower flexible wall to press it against the lower end of the valve carrier, and to close communication from the higher pressure and open communication from the lower pressure to the space between the upper pair of valve seats, whereby the air chamber and space above the upper ilexible wall are slowly exhausted until the lower flexible wall forces the valve carrier to the upper position, whereby the connections will be reversed and air will be quickly exhausted from the space beyond the lower flexible wall and slowly fed to the air chamber and the space beyond the upper iiexible wall.

6. In a milking machine pulsator in combination, a valve carrier with two poppet valves therearound, a body having a bore and two pairs of valve seats therearound, said bore adapted to receive and by its smaller diameter portions loosely guide the carrier with its valves each reciprocable between the two valve seats of the corresponding pair of valve seats, an impermeable flexible partition across each end of the bore, the body having a relatively unrestricted passage of of length, and a communication from the bore beyond each pair of valve seats toy a source of lower fluid pressure, the passages and Valves being so arranged that, when the carrier is at either end of. its movement, it causes a pressure diierential tending to force it to the other end of its movement.

JOHN L. HULBERT. 

